Self-efficacy instruments for type 2 diabetes self-care: A systematic review of measurement properties

Aims To identify currently available self-efficacy instruments for type 2 diabetes self-care and to evaluate the evidence for their measurement properties. Design Systematic review of measurement properties. Data sources The PubMed, Embase and CINAHL databases were searched from their inception to 27 May 2019. Review methods The updated COnsensus-based Standards for the selection of health Measurement INstruments methodology were applied. Results Twelve instruments were identified from 3,665 records. Eight instruments were related to self-efficacy in performing a comprehensive set of the tasks/behaviours for diabetes self-care and the other four addressed specific behaviours related to diabetes self-care, such as insulin management. Most of the 12 instruments were developed based on Bandura's self-efficacy theory as their theoretical background. Overall, sufficient high-quality evidence for measurement properties was seldom identified. The Diabetes Management Self-Efficacy Scale is currently the best instrument, with particularly the 4-factor, 16-item version being demonstrated to have sufficient high-quality evidence for structural and internal consistency and sufficient moderate-quality evidence for reliability and convergent validity. Conclusions None of the instruments evaluated all of the relevant measurement properties. The Diabetes Management Self-Efficacy Scale is currently the most suitable instrument for potential use in practice and research. The measurement invariance across languages, measurement error and responsiveness of this instrument still need be evaluated. Impact This systematic review provides clinicians and researchers with a comprehensive list of available instruments for measuring self-efficacy in diabetes self-care, as well as evidence for helping them to select the most appropriate instrument. Using a psychometrically sound instrument will accurately inform practitioners about the levels of self-efficacy in self-care among patients with type 2 diabetes in practice and avoid threatening the credibility of research studies on self-efficacy in diabetes self-care.